Postage stamps are a very common product which are used on an almost daily basis. Currently, the postage stamps are often the peel-off kind wherein the postage stamp is removably adhered to a backing substrate and when it is desired to affix the postage stamp to an envelope, the postage stamp is removed from the backing substrate, while retaining some of the adhesive thereon, and affixed to the envelope.
The postage stamps have a printed postage value thereon and to mail a letter, the letter must have one or more postage stamps with a cumulative printed postage value amounting to the required postage value to mail the letter based on its weight and/or size. Some stamps are sold for a price higher than the printed postage value with the difference being used to support a charitable cause. For example, there is a postage stamp the purchase of which supports breast cancer research. This postage stamp has a printed postage value required to mail a one ounce letter but costs more. By purchasing such stamps, the purchaser gives the difference between the printed postage value of the stamp and the price of the stamp to a fund which supports breast cancer research.
There is no other known purpose for the difference between the printed postage value of postage stamps and the price of the postage stamps.